A monolithically integrated semiconductor laser rotation sensor/gyroscope that
includes at least two isolated, nonsynchronized semiconductor lasers; at least
one being unidirectional and at least a further one being either a straight-line
laser or a second unidirectional ring laser configured to propagate lasing light
waves in the direction opposite to the first unidirectional ring laser; semiconductor
directional waveguide couplers; a semiconductor Y-junction mixing region; and a
semiconductor photodetector. Evanescently outcoupled signals are routed to a photodetector
for detection of the Sagnac shifted frequencies to discern a beat frequency resulting
from rotation of the chip structure. The straight-line semiconductor laser serves
as frequency reference insensitive to rotation. Directing, filtering, and radiating
unwanted reflections or backscattered light to highly absorbing regions is carried
out with waveguide coupler designs and nonreciprocal couplers and filters.